JP2016113335A - Ceramic conjugate, manufacturing method of adhesive for ceramic conjugation and manufacturing method of ceramic conjugate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic conjugate excellent in stability to thermal impact resistance and thermal expansion, a manufacturing method of an adhesive for ceramic conjugate and an inexpensive manufacturing method of the ceramic conjugate.SOLUTION: There is provided a ceramic conjugate 10 having first and second members 1 and 2 of which at least one is ceramic and adhesive layers 3 and 5 bonding the fist and the second member, the adhesive layers 3 and 5 contain silica of 20 to 50 mass%, magnesia of 3 to 25 mass% and the balance alumina of 40 mass% or more, and includes air bubble 4 of 1 to 10 vol.% based on the total volume.SELECTED DRAWING: Figure 1

Description

  Embodiments disclosed herein relate to a ceramic joined body, a method for producing an adhesive for ceramic joining, and a method for producing a ceramic joined body.

  Conventionally, a method has been proposed in which a bonded body (ceramic bonded body) is produced by bonding two members made of ceramics such as silicon nitride and silicon carbide using an adhesive containing a plurality of types of ceramic particles ( For example, see Patent Documents 1 and 2).

JP 47-34410 A JP 57-42580 A

  However, the ceramic joined body described above has room for improvement in terms of thermal shock resistance and stability against thermal expansion.

  Patent Document 2 proposes adding a rare earth element as an adhesive composition. However, rare earth elements are expensive and an inexpensive bonding method has been required.

  One aspect of the embodiment is made in view of the above, and includes a ceramic joined body excellent in thermal shock resistance and stability against thermal expansion, a method for producing an adhesive for ceramic joining, and a method for producing a ceramic joined body. The purpose is to provide it at low cost.

  A ceramic joined body according to one aspect of the embodiment includes first and second members, at least one of which is ceramic, and an adhesive layer that adheres the first and second members. The adhesive layer contains 20 to 50% by mass of silica, 3 to 25% by mass of magnesia, and the balance contains 40% by mass or more of alumina, and contains 1 to 10% by volume of bubbles with respect to the total volume.

  According to one aspect of the embodiment, a ceramic joined body excellent in thermal shock resistance and stability against thermal expansion, a method for producing a ceramic joining adhesive, and a method for producing a ceramic joined body can be provided at low cost.

Drawing 1 is an explanatory view explaining the outline of the manufacturing method of the ceramic joined object concerning an embodiment. Drawing 2 is an explanatory view explaining an outline of a manufacturing method of an adhesive for ceramics joining concerning an embodiment. FIG. 3 is a flowchart illustrating an example of a method for manufacturing a ceramic bonding adhesive according to the embodiment. FIG. 4 is a flowchart illustrating an example of a method for manufacturing a ceramic joined body according to the embodiment.

  Hereinafter, embodiments of a ceramic joined body, a method for producing a ceramic joining adhesive, and a method for producing a ceramic joined body disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

  Drawing 1 is an explanatory view explaining the outline of the manufacturing method of the ceramic joined object concerning an embodiment. As shown in FIG. 1, the ceramic joined body 10 according to the embodiment includes a first member 1, a second member 2, and an adhesive layer 5 that bonds the first member 1 and the second member 2. Prepare.

  In the ceramic joined body 10 according to the embodiment, at least one of the first and second members 1 and 2 is made of ceramic. Examples of such ceramics include, but are not limited to, silicon nitride, silicon carbide, aluminum nitride, and alumina. The first and second members 1 and 2 can be made of the same or different types of ceramics.

  Further, one of the first member 1 and the second member 2 may be a metal, for example. Specifically, for example, stainless steel, titanium, a titanium alloy, copper, a copper alloy, nickel, molybdenum, tungsten, or the like can be applied as one of the first member 1 and the second member 2. It is not limited.

  The adhesive layer 5 includes alumina, silica, and magnesia. The adhesive layer 5 is obtained by heating, melting, and vitrifying the adhesive (adhesive for ceramic bonding) 3, and the bubbles 4 are present inside, that is, enclose the bubbles 4. Thus, the ceramic bonding body 10 excellent in thermal shock resistance and stability against thermal expansion can be produced by including the bubbles 4 in the adhesive layer 5. The configuration of the adhesive 3 and the manufacturing method thereof will be described later with reference to FIG.

  Next, the adhesive layer 5 will be further described. The adhesive layer 5 contains 40% by mass or more, preferably 40 to 70% by mass, and more preferably 45 to 60% by mass of alumina with respect to 100% by mass of the adhesive layer 5. When the content of alumina is less than 40% by mass, the amount of bubbles 4 included in the adhesive layer 5 decreases, and the adhesive layer 5, the first member 1, and the second member are caused by the stress accompanying thermal expansion of the adhesive layer 5. When one or more of the members 2 are cracked or distorted, leakage may occur when used for members that require hermeticity. In addition, the thermal shock resistance is lowered by such cracks and distortions. On the other hand, if the content of alumina exceeds 70% by mass, the melting point (or softening point) of the glass constituting the adhesive layer 5 increases, and bonding becomes difficult due to difficulty in bonding.

  Further, the adhesive layer 5 contains 20 to 50% by mass, preferably 30 to 45% by mass of silica with respect to 100% by mass of the adhesive layer 5. When the content of silica is less than 20% by mass, the melting point (or softening point) of the glass constituting the adhesive layer 5 is increased, and bonding becomes difficult due to difficulty in bonding. When the silica content exceeds 50% by mass, the amount of bubbles 4 contained in the adhesive layer 5 decreases, and the adhesive layer 5, the first member 1, and the first member are caused by the stress accompanying thermal expansion of the adhesive layer 5. If one or more of the two members 2 are cracked or distorted, leakage may occur when used in a member that requires hermeticity. In addition, the thermal shock resistance is lowered by such cracks and distortions.

  The adhesive layer 5 contains 3 to 25% by mass, preferably 5 to 20% by mass of magnesia with respect to 100% by mass of the adhesive layer 5. When the blending amount of magnesia is less than 3% by mass, the melting point (or softening point) of the glass constituting the adhesive layer 5 becomes high, and the bonding strength becomes low due to difficult adhesion. Moreover, even if the compounding quantity of magnesia exceeds 25 mass%, similarly to the case of less than 3 mass%, the melting point (or softening point) of the glass constituting the adhesive layer 5 becomes high and adhesion becomes difficult. Bonding strength is reduced.

The adhesive layer 5 preferably contains one or more of Na ₂ O, Fe ₂ O ₃ , K ₂ O and CaO as impurities. Specifically, with respect to 100% by mass of the adhesive layer 5, it preferably contains 0.1 to 5% by mass, more preferably 0.5 to 3% by mass of impurities. If the adhesive 3 contains impurities to such an extent that such components can be detected from the adhesive layer 5, the melting temperature of the adhesive 3 decreases. For this reason, the firing temperature at the time of producing the ceramic joined body 10 can be lowered, and the influence on the first member 1 and the second member 2 such as deformation caused by firing can be reduced.

Here, the “alumina content” in the adhesive layer 5 refers to polishing the cross section of the ceramic joined body 10 cut at the joint surface between the first member 1 (or the second member 2) and the adhesive layer 5, It is calculated based on quantitative analysis by EPMA (Electron Probe Micro Analyzer) on the surface of the polished adhesive layer 5. Further, the contents of silica, magnesia, Na ₂ O, Fe ₂ O ₃ , K ₂ O and CaO in the adhesive layer 5 can also be calculated in the same manner as the above-mentioned “alumina content”.

  Further, the adhesive layer 5 contains 1 to 10% by volume, preferably 2 to 5% by volume, of the bubbles 4 with respect to the total volume of the adhesive layer 5. If the amount of the bubbles 4 included in the adhesive layer 5 is less than 1% by volume, one or more of the adhesive layer 5, the first member 1 and the second member 2 due to the stress accompanying thermal expansion of the adhesive layer 5 As a result of cracks and distortions, leakage occurs when used in members that require hermeticity. In addition, the thermal shock resistance is lowered by such cracks and distortions.

  On the other hand, when the amount of the bubbles 4 included in the adhesive layer 5 exceeds 10% by volume, the mechanical strength of the adhesive layer 5 is lowered, and the mechanical strength of the ceramic joined body 10 as a whole may be lowered. . Further, when the amount of the bubbles 4 included in the adhesive layer 5 exceeds 10% by volume, the adjacent bubbles 4 communicate with each other between the first member 1 and the second member 2 by the adhesive layer 5. There may also be a problem that the airtightness cannot be maintained.

  Moreover, 2-20 micrometers is preferable and, as for the average diameter of above-mentioned bubble 4, More preferably, it is 5-10 micrometers. There is no problem even if the average diameter of the bubbles 4 is less than 2 μm, but it is difficult to produce the adhesive layer 5 in which 1 to 10% by volume of the bubbles 4 are uniformly included, and the fine bubbles 4 are connected. Therefore, there is a possibility that the airtightness cannot be maintained or the mechanical strength is lowered. On the other hand, if the average diameter of the bubbles 4 exceeds 20 μm, the mechanical strength may decrease locally and may not be suitable for actual use.

  Here, the “amount of bubbles 4” included in the adhesive layer 5 is a cross section obtained by cutting the ceramic joined body 10 at the joint surface between the first member 1 (or the second member 2) and the adhesive layer 5. The ratio of the area of the region confirmed as bubbles 4 by SEM (Scanning Electron Microscope) observation of the polished and polished surface of the adhesive layer 5 per unit area. The “average diameter of the bubbles 4” refers to a median diameter (d50) obtained based on a diameter distribution when the bubbles 4 observed by the SEM are circularly approximated.

  More specifically, the surface of the polished adhesive layer 5 is magnified by a magnification of 200 to 1000 times by SEM, and after identifying the bubble 4 portion in the field of view, all the identified bubbles 4 are approximated by a circle. And measure their diameter. This operation was repeated in a plurality of fields until the number of bubbles 4 reached 200 or more, and the diameter of the obtained bubbles 4 was statistically processed to determine the median diameter (d50). Further, the area ratio of the bubbles 4 was calculated from the integrated value of the area of the bubbles 4 approximated to a circle with respect to the area of the visual field used. Since the volume ratio of the bubbles 4 included in the adhesive layer 5 is the same numerical value as the area ratio, the calculated area ratio is defined as the volume ratio. There is no limitation on the measurement method as long as the same result can be obtained.

  Moreover, it is preferable that the average bending strength of the ceramic joined body 10 which concerns on embodiment is 30 Mpa or more practically. If the average bending strength of the ceramic joined body 10 is less than 30 MPa, for example, the handling strength is insufficient at the time of use, and problems such as breakage may occur. Here, “average bending strength” is measured at room temperature (5 to 35 ° C.) based on a three-point bending test defined in JIS R1601: 2008.

  Moreover, it is practically preferable that the ceramic bonded body 10 has a thermal shock resistance of 410 ° C. or higher, and more preferably 460 ° C. or higher. Here, “thermal shock resistance” refers to a value measured as follows.

  First, a sample is prepared by joining first and second members 1 and 2 each having a size of 50 mm square and a thickness of 50 mm via an adhesive layer 5 having a thickness of 1 mm. Next, this sample is placed on a brick setter of the same size via pillars placed at the four corners, heated at a high temperature in an electric furnace and maintained at a desired temperature for 1 hour or more, and then quickly from the electric furnace. Take it out and expose it to the air at room temperature. Sequential evaluation is performed while increasing the set temperature from 200 ° C. to 600 ° C. by 50 ° C., and the upper limit of the temperature at which cracking does not occur is defined as the value of “thermal shock resistance”. Note that there is no limitation on the evaluation method as long as the same result can be obtained.

  Next, a configuration of the adhesive 3 shown in FIG. 1 and a manufacturing method thereof will be described with reference to FIGS. Drawing 2 is an explanatory view explaining an outline of a manufacturing method of an adhesive for ceramics joining concerning an embodiment.

  As shown in FIG. 2, the adhesive 3 is a suspension in which ceramic particles containing alumina 6, silica 7, and magnesium carbonate 8 as a magnesia source are dispersed in a liquid dispersion medium 9. When the adhesive 3 is pressed so as to be sandwiched between the first and second members 1 and 2 disposed so as to face each other, and fired together with the first and second members 1 and 2, the bubbles 4 are included, A ceramic joined body 10 including the adhesive layer 5 that bonds the first and second members 1 and 2 is produced.

  Here, the point that the adhesive layer 5 including the bubbles 4 is formed by baking the adhesive 3 will be further described. That is, when the adhesive 3 is fired, ceramic particles containing alumina 6, silica 7 and magnesium carbonate 8 are melted. When the adhesive 3 in which the ceramic particles are melted is cooled, adjacent ceramics are bonded to each other to form a vitrified adhesive layer 5, and the first and second members 1 and 2 are interposed through the adhesive layer 5. The ceramic joined body 10 to which is adhered is produced.

  Further, when the adhesive 3 is baked, water and / or carbon dioxide derived from the magnesium carbonate 8 is generated. Then, traces of water and / or carbon dioxide derived from the magnesium carbonate 8 become bubbles 4 and are included in the adhesive layer 5. Further, the magnesium carbonate 8 from which water and / or carbon dioxide has been removed is contained in the adhesive layer 5 as magnesia (MgO).

  In the method for manufacturing the ceramic joined body 10 according to the embodiment, the average particle diameter of the alumina 6 is preferably 50 μm or less, and more preferably 1 to 10 μm. If the average particle size of the alumina 6 exceeds 50 μm, it may be difficult to appropriately fire the alumina 6 depending on the desired shape and size of the adhesive layer 5. Here, the “average particle diameter of alumina 6” means the median diameter (d50) obtained based on the volume-based particle size distribution converted into a sphere equivalent diameter in a laser diffraction particle size distribution measuring apparatus (wet method). Point to. Moreover, it can measure similarly to the average particle diameter of the alumina 6 also about average particle diameters, such as silica 7 and magnesium carbonate 8 mentioned later. Note that there is no limitation on the measurement method as long as the same result can be obtained.

  Moreover, it is preferable that the average particle diameter of the silica 7 shall be 30 micrometers or less, More preferably, it is 0.5-8 micrometers. If the average particle size of the silica 7 exceeds 30 μm, it may be difficult to appropriately fire the silica 7 depending on the desired shape and size of the adhesive layer 5.

  Moreover, the average particle diameter of the magnesium carbonate 8 is 1-30 micrometers, Preferably it is 3-10 micrometers. When the average particle diameter of the magnesium carbonate 8 is less than 1 μm, there is a concern that the sufficiently large bubbles 4 are not formed. Moreover, when the average particle diameter of the magnesium carbonate 8 exceeds 30 μm, the coarsened bubbles 4 are formed, so that the mechanical strength varies, and there is a concern that the mechanical strength is locally reduced.

  Further, the blending ratio of each component in the adhesive 3 is determined in consideration of the desired composition of the adhesive layer 5. That is, the blending ratio of each component can be set so that the composition of each component constituting the adhesive layer 5 does not deviate from the appropriate range described above.

  Here, the “mixing ratio of the alumina 6 in the adhesive 3” is the mass ratio of the alumina 6 to the ceramic particles that are solid components excluding the dispersion medium 9 in the adhesive 3. It is calculated as follows. That is, it can be calculated based on the amount of alumina 6 measured by drying the prepared adhesive 3, pressing and solidifying the powdered adhesive 3, and performing quantitative analysis using fluorescent X-rays. Further, “the blending ratio of silica 7” and “the blending ratio of magnesium carbonate 8” can be calculated in the same manner as the “mixing ratio of alumina 6”.

  As the dispersion medium 9 for dispersing the ceramic particles containing alumina 6, silica 7 and magnesium carbonate 8, a material that does not erode the ceramic particles and has a relatively high volatility is applied. Specific examples include water, methanol, ethanol, isopropyl alcohol, acetone, and ethyl acetate, but are not limited thereto. A suspension for producing the adhesive 3 can be obtained by dispersing ceramic particles in a single or a mixture of a plurality of these dispersion media 9.

  Here, the ratio of the dispersion medium 9 to 100% by mass of the ceramic particles containing alumina 6, silica 7 and magnesium carbonate 8 can be, for example, 5 to 10% by mass. There is no limitation as long as the adhesive 3 can be applied to the second members 1 and 2. Further, in order to facilitate the application of the adhesive 3 to the first and / or second members 1 and 2, an appropriate amount of one or two or more kinds of dispersants depending on the type of the dispersion medium 9 may be added. .

In the above-described embodiment, the example in which the magnesium carbonate 8 is applied as the magnesia source has been described, but the present invention is not limited thereto. For example, a silica-magnesia ceramic obtained by pulverizing a silica-magnesia fired body obtained by firing a molded body that includes silica particles and magnesia particles in a mass ratio of 1: 1 and is molded by a wet or dry method. You may apply. Such silica-magnesia-based fired bodies and silica-magnesia-based ceramics contain MgSiO ₃ and / or Mg ₂ SiO ₄ .

  When silica-magnesia ceramics are applied instead of magnesium carbonate 8, the average particle size of the silica-magnesia ceramics dispersed in the dispersion medium 9 is 1 to 30 μm, preferably 3 to 10 μm. When the average particle size of the silica-magnesia ceramic is less than 1 μm, there is a concern that the sufficiently large bubbles 4 are not formed. On the other hand, when the average particle diameter of the silica-magnesia ceramic exceeds 30 μm, coarse bubbles 4 are formed, resulting in variations in mechanical strength, and there is a concern that the mechanical strength is locally reduced.

  Such a silica-magnesia ceramic is not only a magnesia source in the adhesive layer 5 but also a silica source. For this reason, when applying such a silica-magnesia ceramic, it is preferable to appropriately adjust the amount of ceramic particles dispersed in the dispersion medium 9 in consideration of this point.

  Further, the degree of pressurization by the first and second members 1 and 2 with the adhesive 3 interposed therebetween is appropriately adjusted according to the hardness (viscosity) of the adhesive 3 used. Furthermore, the firing temperature, firing time, firing atmosphere, and the like are appropriately adjusted according to the materials of the first and second members 1 and 2, the melting temperature of the adhesive 3, and the like. Thereby, the ceramic joined body 10 having a desired shape and characteristics is manufactured. Note that if the firing temperature is lower than 1400 ° C., the reaction of generating bubbles 4 from the magnesia source may not occur sufficiently, so the firing temperature is preferably 1400 ° C. or higher.

  Thus, according to the manufacturing method of the ceramic joined body 10 according to the embodiment, the bubbles 4 are formed based on the magnesia source included in the adhesive 3, thereby being excellent in thermal shock resistance and stability against thermal expansion. A ceramic joined body 10 is generated.

  Next, a method for manufacturing the adhesive 3 according to the embodiment will be described in detail with reference to FIG. FIG. 3 is a flowchart illustrating an example of a processing procedure for manufacturing the adhesive 3 according to the embodiment.

As shown in FIG. 3, first, ceramic particles containing silica 7 and magnesia, which is a magnesia source, are mixed (step S11), and a compact is produced by wet and / or dry methods (step S12). Then, the resulting molded body was fired at the step S12, the silica containing MgSiO ₃ and / or _Mg 2 SiO ₄ - generating a magnesia-based sintered body (step S13).

Subsequently, the silica-magnesia-based fired body is pulverized to produce silica-magnesia-based ceramics (step S14). Further, a suspension is prepared by dispersing the silica-magnesia ceramic obtained in step S14 in the dispersion medium 9 together with alumina 6 and silica 7 (step S15). Through the above steps, the production of the series of adhesives 3 according to the embodiment is completed. When applying as a magnesia source a prepared magnesium carbonate 8, MgSiO ₃ or _Mg 2 SiO _4, step S11~S14 can be omitted.

  Next, a method for manufacturing the ceramic joined body 10 according to the embodiment will be described in detail with reference to FIG. FIG. 4 is a flowchart showing a processing procedure for manufacturing the ceramic bonded body 10 according to the embodiment.

  As shown in FIG. 4, first, ceramic particles containing alumina 6, silica 7, magnesium carbonate 8 as a magnesia source, or silica-magnesia ceramic produced in step S <b> 14 shown in FIG. A dispersed suspension is prepared (step S21). Next, the adhesive 3 made of the suspension prepared in step S21 is applied to the surface of the first member 1 and / or the second member 2 by a known method such as brushing or spraying (step S22).

  Subsequently, pressure is applied with the adhesive 3 sandwiched between the first and second members 1 and 2 (step S23), and further firing is performed (step S24). Through the above steps, the production of the series of ceramic joined bodies 10 according to the embodiment is completed.

  As described above, the ceramic joined body according to the embodiment includes the first and second members, at least one of which is ceramic, 20 to 50% by mass of silica, 3 to 25% by mass of magnesia, and the rest. An adhesive layer that contains 40% by mass or more of alumina, encloses 2 to 10% by volume of bubbles with respect to the total volume, and bonds the first and second members.

  Therefore, according to the ceramic joined body according to the embodiment, a ceramic joined body excellent in thermal shock resistance and stability against thermal expansion can be provided.

  In the above-described embodiment, the first and second members 1 and 2 facing each other are described as sandwiching and pressing the adhesive 3, but the first and second members 1 and 2 are applied to the adhesive 3. And the adhesive 3 and the first and second members 1 and 2 may be brought into close contact with each other, and the arrangement of the first and second members 1 and 2 is not limited.

  In the above-described embodiment, it has been described that the adhesive 3 is pressurized, then fired, and then fired. However, the dispersion medium 9 may be dried as needed before firing.

Example 1
50 by mass ratio of alumina 6 (average particle size 2 μm, purity 99.5%), silica 7 (average particle size 1 μm, purity 99.5%) and magnesium carbonate 8 (average particle size 6 μm, purity 99.5%). : 37:13. Next, an adhesive 3 was obtained by dispersing and suspending these ceramic particles in deionized water (5 mass% with respect to 100 mass% solid content) as a dispersion medium 9 using a stirrer.

  The adhesive 3 is applied to one surface of two plate-shaped silicon carbides (corresponding to the first and second members 1 and 2) prepared in advance using a brush, and the other surface is applied to the adhesive 3 Then, the dispersion medium 9 in the adhesive 3 was dried by being left in a drying chamber at 80 ° C. and a relative humidity of 60% for 5 hours.

  Next, two silicon carbides sandwiching the adhesive 3 were pressed at a press pressure of 5000 Pa, and baked in the atmosphere at a temperature rising rate of 300 ° C./h and a maximum temperature of 1500 ° C. for 4 h. After the completion of firing, the ceramic joined body 10 provided with the adhesive layer 5 was naturally cooled. Table 1 shows the physical properties of the obtained adhesive layer 5 and ceramic joined body 10. In Table 1, “Leakage” and “Leakage after thermal shock” were evaluated as follows.

[Leakage]
First, two cylindrical silicon carbides having an outer diameter of 20 mm, an inner diameter of 16 mm, and a length of 30 mm (corresponding to the first and second members 1 and 2) were prepared. Next, the adhesive 3 is applied to the end surface of the cylindrical silicon carbide, and the two cylindrical silicon carbides stacked so as to sandwich the adhesive 3 are pressed at a press pressure of 5000 Pa, and the temperature rising rate is 300 ° C./h. Firing was performed in the air at a maximum temperature of 1500 ° C. for 4 hours. After the completion of firing, the sample was naturally cooled to obtain a cylindrical test piece (corresponding to the ceramic joined body 10) provided with the adhesive layer 5 having a thickness of 1 mm.

  The opening at one end of the cylindrical test piece was sealed with a rubber plate, and a tube connected to a vacuum pump was attached to the other end. Next, the pressure (vacuum degree (unit: kPa)) obtained after closing the valve with the vacuum pump operated so that the gauge pressure is −90 kPa or less in the atmospheric pressure and leaving it for 4 hours is set to be leaky. It was used as an index.

[Leakage after thermal shock]
A test piece similar to the above-described evaluation of leakability is prepared, held in a furnace set to a temperature obtained by measuring thermal shock resistance for 1 hour or longer, and subjected to thermal shock that is quickly removed from the electric furnace and exposed to room temperature. After that, the same evaluation as the above-described leakage was performed.

(Example 2)
Alumina 6 (average particle size 2 μm, purity 99.5%), silica 7 (average particle size 1 μm, purity 99.5%) and silica-magnesia ceramic (average particle size 5 μm) in a mass ratio of 50:30:20 A ceramic joined body 10 was produced in the same manner as in Example 1 except that each was blended so that The physical properties of the obtained ceramic joined body 10 are shown in Table 1. The silica-magnesia ceramics were produced as follows.

  First, 50% by mass of silica 7 (average particle size 1 μm, purity 99.5%) and 50% by mass magnesia (average particle size 1 μm, purity 99.5%) were weighed so as to have this mass ratio. Subsequently, using a stirrer, these ceramic particles were dispersed and suspended in deionized water (5% by mass with respect to 100% by mass of solids) as a dispersion medium 9 to obtain a suspension. The obtained suspension was dried and pulverized, and then press molded at a press pressure of 30 MPa to obtain a plate-shaped molded body. The molded body was fired in the air for 4 h at a temperature rising rate of 300 ° C./h and a maximum temperature of 1500 ° C. After the completion of firing, the silica-magnesia fired body obtained by natural cooling was pulverized to obtain silica-magnesia ceramics.

(Example 3)
Alumina 6 (average particle size 2 μm, purity 99.5%), silica 7 (average particle size 1 μm, purity 99.5%) and silica-magnesia ceramics produced in the same manner as in Example 2 (average particle size 2 μm) Were weighed to a mass ratio of 41:33:26. Next, using a stirrer, these ceramic particles were dispersed in deionized water (5% by mass relative to 100% by mass of solid content) as a dispersion medium 9 to obtain an adhesive 3. Next, the ceramic joined body 10 was produced in the same manner as in Example 1 except that the first and second members 1 and 2 were made of silicon nitride and fired in an inert atmosphere at a maximum temperature of 1450 ° C. The physical properties of the obtained ceramic joined body 10 are shown in Table 1.

Example 4
Alumina 6 (average particle size 2 μm, purity 99.5%), silica 7 (average particle size 1 μm, purity 99.5%) and magnesium carbonate 8 (average particle size 25 μm, purity 99.9%) in a mass ratio of 57 : Weighed each to be 26:17. Next, using a stirrer, these ceramic particles were dispersed in deionized water (5% by mass relative to 100% by mass of solid content) as a dispersion medium 9 to obtain an adhesive 3. Next, a ceramic joined body 10 was produced in the same manner as in Example 1 except that the maximum temperature was 1530 ° C. The physical properties of the obtained ceramic joined body 10 are shown in Table 1.

(Example 5)
Alumina 6 (average particle size 5 μm, purity 99.9%), silica 7 (average particle size 5 μm, purity 99.9%) and silica-magnesia ceramic (average particle size 8 μm) in a mass ratio of 50:18:42 A ceramic joined body 10 was produced in the same manner as in Example 1 except that each was blended so that The physical properties of the obtained ceramic joined body 10 are shown in Table 1. The silica-magnesia ceramics were produced as follows.

  First, 50% by mass of silica 7 (average particle size 1 μm, purity 99.9%) and 50% by mass magnesia (average particle size 1 μm, purity 99.9%) were weighed so as to have this mass ratio. Subsequently, using a stirrer, these ceramic particles were dispersed and suspended in deionized water (5% by mass with respect to 100% by mass of solids) as a dispersion medium 9 to obtain a suspension. The obtained suspension was dried and pulverized, and then press molded at a press pressure of 30 MPa to obtain a plate-shaped molded body. The molded body was fired for 4 hours in the air at a temperature rising rate of 300 ° C./h and a maximum temperature of 1550 ° C. After the completion of firing, the silica-magnesia fired body obtained by natural cooling was pulverized to obtain silica-magnesia ceramics.

(Comparative Example 1)
Alumina 6 (average particle size 2 μm, purity 99.9%), silica 7 (average particle size 1 μm, purity 99.9%), magnesia (average particle size 1 μm, purity 99.9%) and yttria (average particle size 1 μm) , 99.9% purity) were weighed so that the mass ratio would be 32: 45: 13: 10. Subsequently, these ceramic particles were dispersed in deionized water (5% by mass with respect to 100% by mass of solids) as a dispersion medium 9 using a stirrer, and the same as in Example 1 except that the firing temperature was changed. The ceramic joined body 10 was produced by the method described above. Firing was performed in the atmosphere for 4 h at a temperature rising rate of 300 ° C./h and a maximum temperature of 1500 ° C. The physical properties of the obtained ceramic joined body 10 are shown in Table 1.

(Comparative Example 2)
Alumina 6 (average particle size 2 μm, purity 99.9%) and silica-magnesia ceramics (average particle size 5 μm) produced in the same manner as in Example 5 were weighed so as to have a mass ratio of 70:30. Subsequently, a ceramic joined body was obtained by the same method as in Example 2 except that these ceramic particles were dispersed in deionized water (5 mass% with respect to 100 mass% solid content) as a dispersion medium 9 using a stirrer. 10 was produced. The physical properties of the obtained ceramic joined body 10 are shown in Table 1.

  Table 1 summarizes the physical properties of the ceramic joined body 10 obtained in Example 1 and Comparative Example 2.

  From the above results, the ceramic joined bodies 10 of Examples 1 to 5 include 1 to 10% by volume of bubbles 4 with respect to the entire volume of the adhesive layer 5. All of these ceramic bonded bodies 10 have a thermal shock resistance exceeding 410 ° C., and are superior in stability to thermal shock compared to Comparative Examples 1 and 2 which are conventional materials. At the same time, the ceramic joined bodies 10 of Examples 1 to 5 all have an average bending strength of 30 MPa or more.

In particular, Examples 1 to 4 including one or more of Na ₂ O, Fe ₂ O ₃ , K ₂ O, and CaO as impurities are less leaky and have a thermal shock than Example 5 that does not include impurities. Excellent in terms of later leakage and average bending strength.

  As described above, the ceramic joined body 10 and the adhesive 3 according to the embodiment are suitable for use on a member used at a high temperature or a member to which a large thermal shock is applied, and in particular, a seal portion that requires a tight seal. Suitable for bonding and bonding.

  Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

DESCRIPTION OF SYMBOLS 1 1st member 2 2nd member 3 Adhesive (adhesive for ceramics bonding)
4 Air bubbles 5 Adhesive layer 6 Alumina 7 Silica 8 Magnesium carbonate 9 Dispersion medium 10 Ceramic bonded body

Claims (14)

First and second members, at least one of which is ceramic;
20 to 50% by mass of silica, 3 to 25% by mass of magnesia, and the balance of 40% by mass or more of alumina, containing 1 to 10% by volume of bubbles with respect to the total volume, An adhesive layer for adhering the second member;
A ceramic joined body comprising:   The ceramic bonded body according to claim 1, wherein the thermal shock resistance is 410 ° C or higher.   The ceramic joined body according to claim 1 or 2, wherein an average bending strength is 30 MPa or more.   The ceramic bonded body according to any one of claims 1 to 3, wherein an average diameter of the bubbles is 2 to 20 µm. 5. The ceramic joined body according to claim 1, wherein the adhesive layer further includes one or more of Na ₂ O, Fe ₂ O ₃ , K ₂ O, and CaO.   The ceramic joined body according to any one of claims 1 to 5, wherein the ceramic is silicon carbide. A heating step of firing a molded body containing silica and magnesia to produce a silica-magnesia-based fired body;
Pulverizing the silica-magnesia sintered body to produce silica-magnesia ceramics;
A suspension step of producing a suspension in which ceramic particles containing alumina and the silica-magnesia ceramic are dispersed in a dispersion medium. A method for producing an adhesive for bonding ceramics.   The method for producing an adhesive for bonding ceramics according to claim 7, wherein the ceramic particles further contain silica. A suspension step of preparing an adhesive comprising a suspension in which ceramic particles containing alumina and silica-magnesia ceramics are dispersed in a dispersion medium;
A pressure-contacting step in which at least one of the first and second members made of ceramics is pressure-contacted via the adhesive;
A bonding step in which the first and second members pressed through the adhesive are baked to produce an adhesive layer in which the adhesive is vitrified, and the first and second members are bonded; Including
The adhesive layer contains 20 to 50% by mass of silica, 3 to 25% by mass of magnesia, and the balance contains 40% by mass or more of alumina, and encloses 1 to 10% by volume of bubbles with respect to the total volume. A method for producing a ceramic joined body, comprising:   The method for producing a ceramic joined body according to claim 9, wherein the ceramic particles further contain silica. A firing step of firing a molded body containing silica and magnesia to produce a silica-magnesia-based fired body;
The method for producing a ceramic joined body according to claim 9 or 10, further comprising a pulverizing step of pulverizing the silica-magnesia-based fired body to produce the silica-magnesia-based ceramic.   The method for producing a ceramic joined body according to any one of claims 9 to 11, wherein an average particle diameter of the silica-magnesia ceramic dispersed in the dispersion medium is 1 to 30 µm. A suspension step of preparing an adhesive made of a suspension in which ceramic particles containing alumina, silica, and magnesium carbonate are dispersed in a dispersion medium;
Pressure-contacting the first and second members, at least one of which is ceramic, via the adhesive;
A bonding step in which the first and second members pressed through the adhesive are baked to produce an adhesive layer in which the adhesive is vitrified, and the first and second members are bonded; Including
The adhesive layer contains 40 to 70% by mass of alumina, 20 to 50% by mass of silica, and 3 to 25% by mass of magnesia, and encloses 2 to 10% by volume of bubbles with respect to the total volume. A method for producing a ceramic joined body characterized by   The method for producing a ceramic joined body according to claim 13, wherein an average particle diameter of the magnesium carbonate is 1 to 30 μm.

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